DOI: 10.1249/mss.0000000000003364 ISSN: 1530-0315

A Randomized, Double-Blinded, Placebo-Controlled Clinical Trial Evaluating Transcranial Photobiomodulation as Treatment for Concussion

Alex M. Taylor, Rebekah Mannix, Ralph D. Zafonte, Michael J. Whalen, William P. Meehan
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Orthopedics and Sports Medicine



Literature indicating that transcranial photobiomodulation (tPBM) may enable the brain to recover normal function following concussion, resulting in symptoms reduction and improved cognitive function following concussion is limited by small sample sizes and lack of controls.


We conducted a randomized, double-blinded, placebo-controlled trial examining the effect of 6 weeks of tPBM in patients eleven years or older who received care for persistent post-concussion symptoms between September 2012 and December 2015. Our primary outcome measure was the mean difference in postconcussion symptom scale (PCSS) total score and raw ImPACT composite scores between study entry and treatment completion. Participants received two, ten-minute sessions either with tPBM units or via two placebo units, three times per week. We screened for potential confounding variables using univariable analyses. We entered co-variables that differed between the two groups on univariable screening into a regression analysis. We considered adjusted odds ratio that did not cross one statistically significant.


48 participants completed the study. Most were female (63%) and a majority sustained their injury during sports or exercise (71%). Despite randomization, those that received tPBM therapy reported a greater number of prior concussions. After adjusting for the effect of prior concussions and multiple comparisons, there were no significant differences between tPBM and placebo groups at 3-weeks or 6-weeks of treatment.


Despite showing promise in previous investigations, our study did not show benefit to tPBM over placebo therapy in patients experiencing persistent post-concussion symptoms. Further investigation is needed to determine if varying the dose or timing alters the efficacy of tPBM following concussion.

More from our Archive